Clinical Risk Factors Do Not Predict Shoulder Dystocia

Area of Science:

• Obstetrics and Gynecology
• Perinatal Medicine
• Clinical Risk Prediction

Background:

• Shoulder dystocia is a significant obstetric emergency with potential for severe neonatal and maternal morbidity.
• Accurate prediction of shoulder dystocia is crucial for appropriate management and resource allocation.

Purpose of the Study:

• To compare the predictive performance of two distinct risk factor models for shoulder dystocia.
• To evaluate a traditional model (birthweight, macrosomia) versus a clinical model (estimated fetal weight, suspected macrosomia).

Main Methods:

• Retrospective cohort study of 13,998 vaginal deliveries over 8 years.
• Development and comparison of two multivariable logistic regression models for shoulder dystocia prediction.
• Inclusion of variables such as prolonged second stage of labor, diabetes, and oxytocin use in final models.

Main Results:

• Shoulder dystocia occurred in 1.6% (221/13,998) of deliveries.
• Neither the traditional nor the clinical model demonstrated high sensitivity or specificity.
• No model cutoff threshold yielded a clinically useful positive predictive value (PPV).

Conclusions:

• Shoulder dystocia remains a largely unpredictable clinical event, even in the presence of identified risk factors.
• Current risk factor models have limited utility in accurately predicting shoulder dystocia.
• Further research is needed to improve the prediction and management of shoulder dystocia.